Evaluating the predictive value of osteoarthritis diagnoses in an administrative database.

OBJECTIVE: To assess the positive and negative predictive values of osteoarthritis (OA) diagnoses contained in an administrative database. METHODS: We identified all members (> or =18 years of age) of a Massachusetts health maintenance organization with documentation of at least one health care encounter associated with an OA diagnosis during the period 1994-1996. From this population, we randomly selected 350 subjects. In addition, we randomly selected 250 enrollees (proportionally by the age and sex of the 350 subjects) who did not have a health care encounter associated with an OA diagnosis. Trained nurse reviewers abstracted OA-related clinical, laboratory, and radiologic data from the medical records of both study groups (all but 1 chart was available for review). Pairs of physician reviewers evaluated the abstracted information for both groups of subjects and rated the evidence for the presence of OA according to 3 levels: definite, possible, and unlikely. RESULTS: Among the group of patients with an administrative diagnosis of OA, 215 (62%) were rated as having definite OA, 36 (10%) possible OA, and 98 (28%) unlikely OA, according to information contained in the medical record. The positive predictive value of an OA diagnosis was 62%. In those without an administrative OA diagnosis, 44 (18%) were assigned a rating of definite OA. The negative predictive value of the absence of an administrative OA diagnosis was 78%. CONCLUSION: Use of administrative data in epidemiologic and health services research on OA may lead to both case misclassification and under ascertainment.

Body weight, body mass index, and incident symptomatic osteoarthritis of the hand, hip, and knee.

Studies have shown a positive association between obesity and knee osteoarthritis. Studies evaluating hand or hip osteoarthritis and weight, however, have assessed x-ray osteoarthritis or been cross-sectional, or both, and results of these have been inconsistent. We assessed the association between body weight, body mass index, and incident symptomatic osteoarthritis in 134 matched case-control pairs of women who were part of a case-control study on estrogen replacement therapy and osteoarthritis. We identified incident symptomatic osteoarthritis cases of the hand, hip, and knee in women ages 20-89 years who were members of a health plan between January 1, 1990 and December 31, 1993. For each case we selected a control woman who was matched by closest date of birth to the case. Medical records were reviewed to obtain weight and height information for the period before disease onset. After controlling for estrogen use, smoking status, height, and health care use, we found that body weight was a predictor of incident osteoarthritis of the hand, hip, and knee. Odds ratios ranged from 3.0 to 10.5 for women in the upper tertiles of weight compared with women in the lowest tertile. Similar associations were observed for body mass index. Our results suggest that obesity is associated with the development of incident osteoarthritis at all joints studied.

Estrogen replacement therapy and urinary tract infections in postmenopausal women aged 45-89.

OBJECTIVE: An elevated risk of urinary tract infections (UTIs) in postmenopausal women has been attributed to an increase in the vaginal pH. Estrogen replacement therapy (ERT) helps restore the vaginal milieu and may have a beneficial effect on risk of infection. Studies examining the association between ERT and UTIs have been inconsistent. We conducted a nested case control study to clarify this relationship in women aged 45-89. DESIGN: For each case, we selected up to five control women, matched by year of birth. We used pharmacy records to classify women as new users, past users, ongoing users (past and new users), and never users of ERT. There were 254 cases and 1,268 controls. RESULTS: The risk ratio for UTI was 1.02 [95% confidence interval (CI) 0.74, 1.40] for any use versus never use, after adjustment for health care utilization. The risk ratio for the association between new use and UTI was 1.13 (95% CI 0.46, 2.77). For ongoing users the risk ratio was 1.08 (95% CI 0.76, 1.54), whereas the risk ratio for past use was 0.77 (95% CI 0.39, 1.48). CONCLUSIONS: Our results do not support a protective effect of ERT on the risk of UTIs.

Estrogen replacement therapy and the development of osteoarthritis.

Recent studies have indicated that estrogen users have a lower than expected rate of concurrent osteoarthritis. We assessed the association between estrogen replacement therapy and incident symptomatic osteoarthritis, using a nested case-control design. We identified all incident cases of hand, hip, and knee osteoarthritis in women members of the Fallon Community Health Plan, age 20-89 years, from January 1, 1990, to December 31, 1993. For each case, we selected a control woman matched by closest date of birth. We used pharmacy records to classify women as new users, past users, ongoing users (past and new users), and never-users of estrogen replacement therapy. There were 60 informative case-control pairs. After controlling for obesity and health care utilization, we found that new use of estrogen replacement therapy was a predictor of new osteoarthritis diagnosis. Past use was inversely associated with risk of osteoarthritis [adjusted odds ratio = 0.7; 95% confidence interval (CI) = 0.3-1.9]. For ongoing use of estrogen replacement therapy and osteoarthritis, the adjusted odds ratio was 1.4 (95% CI = 0.6-3.3). The associations between osteoarthritis and both new use of estrogen replacement therapy and utilization of services suggest that frequent medical care increases the likelihood of diagnosis of osteoarthritis.

Incidence of symptomatic hand, hip, and knee osteoarthritis among patients in a health maintenance organization.

OBJECTIVE: To quantify the incidence of symptomatic hand, hip, and knee osteoarthritis (OA) among members of the Fallon Community Health Plan, a health maintenance organization located in central Massachusetts. METHODS: Incident OA was defined as the first evidence of OA by radiography (grade > or = 2 on the Kellgren-Lawrence scale of 0-4) plus joint symptoms at the time the radiograph was obtained or up to 1 year before the radiograph was obtained. RESULTS: The age- and sex-standardized incidence rate for hand OA was 100/100,000 person-years (95% confidence interval [95% CI] 86, 115), for hip OA 88/100,000 person-years (95% CI 75, 101), and for knee OA 240/100,000 person-years (95% CI 218, 262). The incidence of hand, hip, and knee OA increased with age, and women had higher rates than men, especially after age 50. A leveling off or decline occurred for both groups around the age of 80. CONCLUSION: In a large study of symptomatic OA we observed incidence rates that increased with age. In women ages 70-89, the incidence of knee OA approached 1% per year.

The risk of abscess from sternoclavicular septic arthritis.

From a systematic review of the literature on septic arthritis and our own patient records we found that in a high percentage of cases (20% of those we reviewed) infection of the sternoclavicular joint leads to an abscess. This appears to be true regardless of the presence or absence of a history of intravenous drug abuse or underlying illness compromising the immune system, and regardless of the responsible organism. The predisposing factors must center on the joint itself. The risk from spread of infection should be considered in management of the uncommon but difficult clinical problem of sternoclavicular septic arthritis.

Arthritis in rabbits induced by killed Neisseria gonorrhoeae and gonococcal lipopolysaccharide.

Intraarticular injections of viable N, gonorrhoeae, killed N. gonorrhoeae or gonococcal lipopolysaccharide (LPS) in rabbits' knees caused an acute, polymorphonuclear synovitis with abscess formation 24-72 h after the injection. At 5-7 days, a mononuclear infiltration with synovial lining cell hyperplasia developed, which in some rabbits persisted for one month. Gonococcal LPS, in amounts of 5 micrograms or greater, always caused a marked synovitis indistinguishable from that produced by viable N. gonorrhoeae. Gonococcal outer membrane protein used as a control in these experiments caused no or minimal synovitis in concentrations 50-fold higher than those used in the LPS inoculation experiments. These studies should provide a model to investigate the role of LPS in the arthritis associated with gonococcal infection.